Design and analysis of a novel coupled inductor structure with variable coupling coefficient

Abstract

This study presents a new coupled inductor magnetic structure with variable coupling coefficient. The new symmetrical magnetic structure is composed of stacked ferrite cores, where control legs are placed in the centre of the core structure, on equal distances from the outer legs. In that way, the coupling coefficient is controlled by the means of a DC current. The DC control flux is confined only to the control legs and it is equally balanced in both of the outer legs. Distribution of the control DC flux in the proposed structure is verified applying finite element analysis simulation of the three-dimensional model. Electrical properties of the new variable coupled inductor are derived applying analytical modelling and verified by experiments. Maximal variations of the controlled coupling coefficient value in respect to the different value of the leakage flux are obtained and presented. Design and experimental results are presented for application in an interleaved boost converter with a variable coupled inductor, achieving boundary conduction mode over a wide load variation.

Review of Flux Interaction of Differently Aligned Magnetic Fields in Inductors and Transformers

“…In contrast to transductors, the auxiliary bias winding is usually wound on the outer legs of the magnetic core while the main winding is wound on the center limb. Especially during the last decade, many investigations on parallel biasing were made, e. g. to reduce the size of the magnetic core or to improve its geometry, as it is shown in [18] and [19]. References [20] and [21] present investigations on magnetic flux optimization in variable inductors.…”

Design of a switched‐capacitor boost converter utilizing magnetic coupling with capability of right‐half plane zero elimination

“…In the last decades, several new dc/dc conversion circuits are designed and developed with features of boosting voltage. Some of them utilize switched-capacitors (SCs) [6][7][8][9], coupled inductors (CIs) [10][11][12][13], switched-inductors (SIs) or CIs along with SCs [14][15][16][17] to provide high gains. Also, interleaved configuration-based converters with ultra-large step voltage ratio have been reported in [18,19] and dc/dc converters with cascade quasi-Z-source networks have been presented in [20,21].…”

Four‐phase interleaved TCM DC‐DC buck converter with matrix inductor in battery charging application

“…The high current ripple will limit the design of the core due to size and loss. Two-phase and four-phase interleaved DC-DC converter with inverse coupling and direct coupling are employed to reduce the core loss and winding loss [16][17][18][19][20][21][22][23]. However, the core size is still an issue and the coupling coefficient is not easy to control.…”